Hi there,

this is a game I played today as Black. I know, that I won by a huge tactical blunder at White 105 and others by my opponent and that I made several mistakes, too. But I'm interested in what you can say about the moves around Black 88 and Black 90. I think, I should have played D18 instead of Black 90. What do you think is correct?
(Of course, I'm happy about other comments, too.)

I think you are right. Your 90 fails because of 91@g17. D18 looks promising because then W can't save both f17 and the corner as far as I can read.

22: Try to get in the habit of maintaining as many liberties as you can, unless your group is absolutely alive. In this instance, you have to play P19 sometime in the next few moves regardless of how it is done. When you play Q19 first, and he replies with R19, you have to play P19 anyway.

By exchanging Q19 for R19, all you have done is played a yose move early - one that was sente for you and gote for him. This is aji keshi. You could have had a ko threat there, but now you don't.
The most important shortcoming of Q19 is that you lose a liberty. Set up the position at move 34 on a board. Then remove the two stones at Q19 and R19. Notice that you can play it much differently. If you had one more liberty, you could have played O13 and saved your cutting stones.

54: Saving this stone is more trouble than it is worth. It already has 2 of its 4 liberties filled. In other words, it is half dead already. Let him spend a move or two killing it. If he is lucky, the best he can do is live small and in gote while you build power by chasing him with moves like G11.

60: He has a very vulnerable corner here. I'm too lazy to read out what is best, but D18 looks good enough.

88: L17 works.

90: I'm not sure that there is a good move here. If you play D18, he replies F18 and I think he wins the liberties race.

The important thing is not to find the best move for 90, but rather not to get into potitions like that. If you watch your liberties a little more, you will win these games easily.

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Thank you for your hints. I really appreciate them.

: you should be very happy to connect at Q15, in sente.

Thank you EdLee, that's obviously right. R16 was the first sente move I saw and I played it. I need to focus a lot more.

Yes, R16 is a bad sente move -- the R16 stone ( ) is quite useless for you.